The invention relates to a rigid shaped body, such as a plate or a pipe, comprised of a pluraity of superposed and/or adjacently laminated, commonly pressed, oriented, i.e., stretched thermoplastic carriers in film, ribbon, monofil or fiber form.
By orienting thermoplastics, it is possible to change their physical properties. In particular, partially crystalline materials will exhibit elevated yield stress, resistance to tearing, puncture resistance, low-temperature resistance and transparency as well as a reduced breaking elongation. Big-scale drawing processes are primarily employed, normal to the running direction, for the production of products having small geometric dimensions, such as, for instance, films, film ribbons, monofils and fibers.
For the production of shaped bodies having larger geometric dimensions, it is known (European patent application No. 0,031,157) to commonly press stretched partially crystalline thermoplastic films of equal material upon pressure and temperature exposure. In doing so, the pressing temperature must be raised close to the temperature of the crystallite melting end of the film in order to obtain a sufficient motility of the molecule chains of the plastic films, because it is only then that a sufficient bonding adhesion will be provided. Such a high pressing temperature involves a relaxation of the orientation of the film, thus reducing the favorable properties attained by the drawing process. By the known method, it is, therefore, not possible to produce shaped bodies of larger dimensions that exhibit similarly good properties as the stretched carrier films.